The present invention relates to a message traffic control in data communications with terminals. More particularly, the present invention relates to an on-line data processing system which provides traffic control over the message queuing buffers that temporarily store sent/received messages in accordance with the priority set on the messages in order to absorb the difference in the processing speed between terminals and the on-line program.
The present invention further relates to an on-line data processing system which provides traffic control over message queuing buffers in accordance with the priority set on the messages in the message queuing control for storing and fetching messages into and from the message queuing buffers to thereby ensure the transmission/reception of high priority messages even if a high load is imposed on the on-line program unit in message transmission/reception with terminals.
In on-line data processing systems having a plurality of terminals and a host computer connected via communication lines, hundreds to thousands of terminals are generally connected, and depending on the usage period, time slot, and business application, the on-line data traffic generated varies moment by moment and can, at times, exceed the processing power of the host computer. In addition to such variations in the traffic, there is a limit to the capacity and capability of communication lines such that it may not be possible to properly receive/transmit messages from/to terminals. In general, to resolve these problems and achieve a smooth system operation, buffers to temporarily store received/transmitted messages from/to terminals are implemented accordingly with the processing power of the host computer and the capacity and capability of the communication lines. And depending on the buffer usage status, traffic control is exercised to restrain messages being received from terminals by transmitting restraining messages and by following transmission control protocols as well as to restrain message transmissions to terminals by on-line programs such as business programs running on the host computer.
However, a conventional traffic control has been provided irrespective of the type and/or processing priority of messages as well as not over message queuing buffers in accordance with the priority set on messages.
Since in such a conventional traffic control system the traffic control is provided without discriminating sent/received messages with terminals in accordance with the type and processing priority of the messages, a high emergency message cannot be transmitted/received when a high load is imposed on the on-line program. Even if a transmission/reception is made, on-line data processing of that message can be delayed, disadvantageously. Especially, an on-line system which requires updating a data base, for example a banking system, can be greatly influenced by such drawbacks.
The present invention eliminates such drawbacks in the conventional techniques. It is an object of the present invention to provide a traffic control device which ensures the transmission/reception of high priority messages.